Tall oil treatment



Patented Apr. 17, 1945 asiasrs TALLOIL TREATMENT Ernest Segessemann,Newark, N. 1., assignorto National Oil Products Company, Harrison, N.J., a corporation of New Jersey No Drawing. Original applicationDecember 16,

1939, Serial No. 309,703. Divided and this application January 1, 1942,Serial No. 425,346

3 Claims. (Cl. zoo-97.5)

This invention relates in general to the production of valuable productsfrom tall oil, and more particularly to a process of separating tall oilinto ts main constituents; i. e. fatty and resinic acids. The presentinvention is especially directed to the recovery of valuable productsfrom tall oil without subjecting the same to any extensive degree ofhydrogenation or esterification, my copending application Serial No.309,703, now Patent No. 2,305,498, of which this is a division, beingdirected to a similar process during which the tall oil is subjectedtohydrogenation to varying extents; my copending application Serial No.425,348 filed concurrently herewith being directed to a similar processin which the tall oil is esterified to varying extents; and my copendingapplication Serial No. 425,357 filed concurrently herewith beingdirected to a similar process in which the tall oil is both esterifiedand hydrogenated to varying extent-s.

Tall oil or talloel, which literally means pine oil, is the resinous andfatty by-product obtained chiefly in the production of paper pulp fromresin-bearing woods by the so-called sulphate process. In the sulphateprocess wood is digested with an alkaline liquor containing sodiumsulphate, during which process tall oil ac-' cumulates in the form ofits sodium soap on the surface of the waste liquor. The mainconstituents-of this oil, after acidification, comprise resinic acidsand fatty acids, the latter consisting mainly of oleic, linoleic. andlinolenic acids, each of which is a valuable commodity in substantiallypure form. Various processes have been proposed in an attempt to effectseparation of tall oil into its main constituents, i. e. fatty acids andresinic acids. One process comprises esterifying the fatty acids in tall011 with a low boiling alcohol and separating the resulting fatty esterfrom the free rosin acids by distillation or by alkali extraction.Another known process comprises esterifying the fatty acids with apolyhydric alcohol and distilling off the resinic acids. According toanother process, both the fatty acids and the resinic acids areesterified with a polyhydric alcohol and the resin esters are thencatalytically split and the liberated resinic acids distilled off. Whilethe foregoing and other known processes have been employed with varyingdegrees of success, they all exhibit certain disadvantages, primarily inthat only partial separation is effected. Moreover, the fatty acidfraction obtained by these processes, consisting mainly of a mixture ofoleic, linoleic and linolenic acids, is not particularly suitable for awide variety of industrial uses. Usually having an iodine value of about120 to 130, this fatty acid fraction (or its esters) shows some dryingproperties, but these drying properties are not pronounced enough for adrying oil of good quality. On the other hand, this fatty acid fractionis too highly unsaturated to find extensive application in some of thelargest fat-consuming industries, namely the soap industry'and in themanufacture of specialties for the textile and tanning trades, the

bulk of fats used in these industries being of a more highly saturatedtype.

The general object of this invention is to obviate the foregoing andother disadvantages.

' A specific object of the invention is to provide an improvedand moreefiicient process for sepa rating tall oil into fractions having morevaluable properties thanthe original tall oil.

A further object of the invention is to provide an improved process forseparating tall oil into its constituents and recovering therefrom themore saturated fatty acids so that the same can be adapted to a wideindustrial use.

Still another object is to recover from tall oil a more highlyunsaturated fraction suitable for many technical applications.

Other objects will in partbe. obvious and will in part appear hereafter.

The foregoing and other objects are acconi plished according to thebroader aspects of the invention whereby tall oil is dissolved in asuitable solvent and subjected to temperatures sufficiently low toeifect precipitation of a certain fraction of, or all of, the fattyacids therein. In general, if lower temperatures are employed, a largerproportion of the more unsaturated fatty acids, such as linoleic acid,will be precipitated, and conversely, if higher temperatures are em-'ployed, a larger proportion of these more unsaturated fatty acids areretained in solution, and only the more saturated fatty acids, such asoleic acid-are precipitated. Thereafter, the said precipitated fractionis removed by filtration or centrifuging or by any other known means ofsep arating an insolublesolid from a liquid. The re I sinic acids aloneor in admixture with the mor highly unsaturated fatty acids remaining inth solvent may be recoveredby distilling off the solvent.

The tall oil employed in accordance with the process of the presentinvention may be in the crude or distilled state .and it may besubjected to some slight degree of hydrogenation'and/or.

esterification before being subjected to the chill-- ing and separatingsteps. However it is not in'- tended to cover in this application the-treat-' ment of tall oil which has been subjected to any considerabledegree of'hydrogenation and/or esterification, this subject matter beingdisclosed and claimed in my copending applications above referred to.Accordingly, the filtrate obtained upon separation of the precipitatedfatty acids will also contain fatty acids of the more highly unsaturatedtype, mostly linoleic and linolenic acids. These higher unsaturatedfatty acids may then be separated from the rosin by esterificatlonfollowed by alkali extraction of the rosin, or by methods disclosed inmy copending applications, Serial Nos. 217,974 and 303,535, filed July7, 1938, and November 9, 1939, respectively. Alternatively, the mixtureof rosin acids and higher unsaturated fatty acids may be used as such inthe preparation of other products such as drying oils, which is to formthe subject matter of another application.

This invention accordingly comprises the several steps and the relationof one or more ofsuch steps with respect to each of the others thereof,which will be exemplified in the process hereinafter disclosed, and thescope of the invention will be indicated in the claims.

solvents include, inter alia, petroleum hydrocarbons, such as, gasoline,kerosene, heptane, mineral spirits, etc.; aromatic hydrocarbons, such asbenzene, toluene, xylene, etc.;- alcohols, such as ethyl alcohol, methylalcohol, isopropyl alcohol, etc.; ketones, such as acetone, ethyl methylketone, cyclohexanone, etc. chlorinated hydrocarbons, such as ethylenedichloride, trichlorethylene, etc.

After the tall oil has been dissolved in a suitable solvent, thetemperature of the solution is decreased to obtain the desired degree ofprecipitation of fatty acids thereof. By actu'al experiment, atemperature range of about 5C. to 70 C. will accomplish this result. Itis obvious, of course, that temperatures outside of this range may alsobe operative to carry out the objects of the invention. The degree ofcooling will be varied according to the nature of the solvent used andaccordin to the form in which the fatty and resinous materials occur.The degree of cooling will be further varied according to the productdesired, lower temperatures being required when it is desired to removea larger portion of thefatty acids, particularly the more highlyunsaturated fatty acids such as linoleic. from the solution. Theprecipitated fatty acids are removed from the solvent solution by anysuitable means including centrifuging and filtration. The precipitatedproducts after removal are preferably washed with a suitable solvent, e.g. the same solvent as used in the process, and preferably atsubstantially the same temperature at which the precipitating operationwas carried out.

For a fuller understanding of the nature and objects of the invention,reference should be had to the following examples, which are givenmerely to illustrate the invention and arenot to be construed in alimiting sense.

Example I 100 gms. of distilled tall oil (having a rosin content of 32%)were dissolved in 650 ml. of

acetone and cooled to -60 C. for 1 hour. The oleic acid fraction whichcrystallized out was then filtered off and washed with 350 ml. of fresh,

acetone which had previously been cooled to -60 C. 40 gms. of fattyacids were obtained iii! sixth hour.

From the filtrate the solvent was distilled off and the residueconsisting mainly of rosin, linoleic and linolenic acids was esterifiedby heating gms. of it with 5.5 gms. of anhydrous glycerol at such a ratethat the temperature gradually rose and reached 280 C. at the end of theThe product thus obtained had excellent film-forming properties and wassuitable for use in the manufacture of varnishes as a substitute forlinseed oil and ester gum.

Example II 100 ms. of distilled tall oil were dissolved in 700 ml. ofethyl alcohol. The solution was maintained at C. for two hours, and thecrystallized fatty acids were filtered and washed with fresh alcoholwhich had previously been cooled to .60 C. The filter cake was freedfrom any residual alcohol by vacuum distillation. 42 gms. of rosin-freefatty acids were obtained having an iodine value of 71.5 and anunsaponifiable content of 1.8%.

To the above filtrate there was added 0.35 gm. of sulphuric acid and themixture was refluxed for four hours. The sulphuric acid was thenneutralized with an equivalent quantity of caustic soda and the excessalcohol was recovered by vacuum distillation. The residue was thendissolved in 209 ml. of commercial heptane and caustic soda 0f 12%strength was added with rapid stirring in an amount 10% .in excess ofthat needed to neutralize the rosin acids. The rosin soap which settledto the bottom of the vessel was then drawn off and was washed once with100 ml. of -heptane. The solution of the ethyl esters in heptane wasthen washed with water until the last traces of soap had been removedand finally the heptan was distilled oil? to recover the ethyl esters ofthe highly unsaturated fatty acids.

The rosin soap was then dissolved in water and split with sulphuric acidto recover the rosin in a free state.

Since certain changes may be made in carrying out the above processwithout departing from the scope of the invention, it is intended thatall matter contained in the above description shall be interpreted asillustrative and not in a limit ing sense.

It is also to be understood that the following claims are intended tocover all the generic and specific features of the invention hereindescribed. and all statements of the scope of the invention, which as amatter of language might be said to fall therebetween.

Having described my invention, what I claim as new and desire to secureby Letters Patent, is:

l. A process of treating tall oil to separate a fatty fraction therefromwhich comprises dissolving the tall oil in ethanol, decreasing thetemperature of the solution to effect precipitation of a fatty fractionand removing the precipitated fraction from the remaining solution..

2. A process of treating tall oil to separate fatty acids therefromwhich comprises dissolving the tall oil in ethanol, decreasing thetemperature of the solution to effect prmipitation of fatty acids andremoving the precipitated fatty acids from the remaining solution.

3. A process of treating tall oil to separate oleic acid therefrom whichcomprises dissolving the tall oil in ethanol, decreasing the temperatureof the solution to effect precipitation of oleic acid and removing theprecipitated oleic acid from the remaining solution.

ERNEST SEGESSEMANN.

